This math topic focuses on calculating factorial expressions in the context of probability and statistics. It primarily deals with solving expressions of the form 1 over the product of factorials and simple arithmetic operations within factorials. The problems involve evaluations such as \( \frac{1}{{n! \times (m-k)!}} \), where n, m, and k are integers. This provides foundational understanding and practice in manipulating factorials, an integral part of solving more complex probability and statistical problems. Each question presents multiple-choice answers, aiding in reinforcing comprehension and calculation skills related to factorial manipulations.